Method for limiting a height of a hospital bed using an elevation mechanism

ABSTRACT

A method for detecting an exit of a patient from a hospital bed, the method comprising: detecting a presence of the patient on the bed; upon detection of the patient on the bed, monitoring an indication that the patient has moved from a predetermined patient area on a patient receiving surface of the bed to outside the predetermined patient area; upon detection that the patient has moved outside the predetermined patient area, activating a bed alarm to indicate to a user that an exit of the patient from the hospital bed has been detected. There is also provided a system for detecting an exit of a patient from a hospital bed. There is further provided a method for limiting a height of a hospital bed and a method for recalibrating a tare weight condition of a hospital bed.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a divisional application of U.S. application Ser. No. 15/818,248filed Nov. 20, 2017, which is incorporated herein by reference.

TECHNICAL FIELD

The present relates to hospital beds, and more specifically to patientexit detection methods and systems for hospital beds. The present alsorelates to methods and systems for limiting a height of a hospital bed,and to methods and systems for recalibrating a tare weight condition ofa hospital bed.

BACKGROUND

Hospital beds and long term care beds are adapted to receive patientsand to allow caregivers to monitor the patient and provide care to thepatient.

Some hospital beds are provided with a system which detects a patientexiting the bed and which issues an alarm in response to alert acaregiver near the bed or remote from the bed. In some cases, thepatient exit from the bed could be detected when the patient moveswithin a certain distance of the sides of the bed's deck.

Unfortunately, this system has a number of limitations. For example, ifa bed exit alarm is triggered and the alarm is then deactivated whilethe patient is still in a location on the bed which indicates a possiblebed exit, the bed exit alarm could be immediately be reactivated,therefore requiring the caregiver to once again deactivate the alarm.

Moreover, when the caregiver wishes to provide care to a patient, he/shewill usually disable the bed exit alarm to be able to move the patienton the bed without running the risk of activating the alarm.Unfortunately, the caregiver may forget to re-arm the system once thepatient has been tended to.

Hospital beds also sometimes include an integrated weight sensor orscale to measure a weight of a patient on the bed while allowing thepatient to remain on the bed. It will be appreciated that hospital bedsare often provided with medical equipment which can vary from patient topatient and which has a certain weight. To obtain a precise measurementof the patient's weight, an initial tare weight condition is thereforemeasured without the patient in the bed, and the initial conditioncorrespond to a “zero” to which the measured parameters will becompared. The initial tare weight condition may comprise a weightmeasurement from the weight sensor. Once the patient is received on thebed, the patient's weight will therefore correspond to the differencebetween the measured weight and the In hospital beds provided with apatient location sensor, the initial tare weight conditions may alsocomprise a location measurement from the patient location sensor.

Unfortunately, the caregiver operating the hospital bed may mistakenlycause the system to perform a measurement of the initial tare weightcondition while the patient has already been positioned on the bed. Inthis case, the bed will therefore no longer properly indicate thepatient's weight. To re-measure the initial tare weight condition toobtain a proper measurement, the patient would have to be removed fromthe bed, which can be time consuming, cumbersome and even harmful to thepatient.

Some hospital beds further include an elevation assembly which allowsthe bed's deck receiving the patient to be selectively raised andlowered. In some cases, medical equipment or other items may be placedunder the bed's deck. Unfortunately, if the bed is lowered towards theground surface under the deck, it may come in contact with the medicalequipment or other items under the bed, which may damage the bed or themedical equipment or other items.

There is therefore a need for a system and a method which would overcomeat least one of the above-identified drawbacks.

BRIEF SUMMARY

According to one aspect, there is provided a method for detecting anexit of a patient from a hospital bed, the method comprising: detectinga presence of the patient on the bed; upon detection of the patient onthe bed, monitoring an indication that the patient has moved from apredetermined patient area on a patient receiving surface of the bed tooutside the predetermined patient area; upon detection that the patienthas moved outside the predetermined patient area, activating a bed alarmto indicate to a user that an exit of the patient from the hospital bedhas been detected.

In one embodiment, detecting the presence of a patient on the bedcomprises: providing a weight sensing assembly operatively connected tothe bed to measure a weight of a patient received on the patientreceiving surface; receiving an indication from the weight sensingassembly that the patient is received on the bed.

In one embodiment, receiving an indication from the weight sensingassembly that the patient is received on the bed comprises: the weightsensing assembly detecting a weight above a predetermined weightthreshold on the bed; the weight sensing assembly providing theindication that the patient is received on the bed.

In one embodiment, the predetermined weight threshold is 32 kg.

In one embodiment, the method further comprises: after detecting thepresence of the patient on the bed, detecting that the patient is in thepredetermined patient area.

In one embodiment, the method further comprises: after monitoring theindication that the patient has moved from the predetermined patientarea and further upon receiving a pause command, suspending monitoringthe indication that the patient has moved from the predetermined patientarea.

In one embodiment, suspending monitoring the indication that the patienthas moved from the predetermined patient area comprises: suspendingmonitoring the indication that the patient has moved from thepredetermined patient area for a predetermined pause time.

In one embodiment, the method further comprises: displaying a timeindicative of an amount of time remaining before expiration of thepredetermined pause time.

In one embodiment, the method further comprises: increasing the amountof time remaining before expiration of the predetermined pause time by apredetermined time increment.

According to another aspect, there is further provided a bed exitdetection system for a hospital bed, the hospital bed including apatient receiving surface, the system comprising: a weight sensingassembly operatively connected to the bed to measure a weight of apatient received on the bed; a patient location sensor operativelyconnected to the patient receiving surface for determining a location ofthe patient on the patient receiving surface; a user interface forreceiving inputs from a user; a display for providing visual indicationsto the user; a bed exit alarm configured for providing an indication toa user that an exit of a patient from the patient receiving surface isdetected; a processing unit operatively connected to the weight sensingassembly, the patient location sensor, the user interface, the displayand the bed exit alarm, the processing unit being configured to receivefrom the weight sensing assembly an indication that the patient isreceived on the bed, the processing unit being further configured toreceive from the patient location sensor an indication that the patienthas moved from a predetermined patient area on the patient receivingsurface to outside the predetermined patient area, thereby indicating anexit of the patient from the bed, the processing unit being furtherconfigured for activating the bed exit alarm when the exit of thepatient from the bed is detected.

In one embodiment, the user interface and the display include a commontouchscreen.

According to yet another aspect, there is provided a method for limitinga height of a hospital bed, the hospital bed including an elevationmechanism for moving a patient receiving surface of the bed verticallyrelative to a ground surface, the method including: providing anindication of a minimum height value to a processing unit operativelyconnected to the elevation mechanism; providing a current height of thebed to the processing unit; detecting a downward vertical movement ofthe elevation assembly; the processing unit comparing the current heightof the bed with a predetermined minimum height value; if the currentheight of the bed is below the predetermined minimum height value,stopping the downward movement of the elevation assembly.

In one embodiment, providing a providing a current height of the bedcomprises: providing an indication of a caster height of bed casters tothe processing unit; the processing unit receiving from a height sensoroperatively connected to the elevation mechanism a current height of theelevation mechanism; the processing unit calculating the current heightof the bed based on the indication of the caster height and the currentheight of the elevation mechanism.

In one embodiment, stopping the downward movement of the elevationassembly comprises: the processing unit providing a command to theelevation mechanism to stop downward movement of the elevation assembly.

In one embodiment, the method further comprises: if the current heightof the bed is below the predetermined minimum height value, providing anindication to a user that the patient elevation surface is at thepredetermined minimum height value.

According to still another aspect, there is also provided a method forrecalibrating a tare weight condition of a hospital bed, the methodcomprising: providing a weight sensing assembly operatively connected tothe bed; measuring a tare weight of the bed provided with medicalequipment without a patient being received on the bed; storing themeasured tare weight in a memory; providing the patient on the bed; uponreceiving a command from a user, replacing the measured tare weight witha previously measured tare weight stored in the memory.

In one embodiment, the method further comprises: calculating a weight ofthe patient based on the stored tare weight.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing a hospital bed system for a hospitalbed, in accordance with one embodiment, in which the hospital bed systemincludes an exit detection system.

FIG. 2 is a flowchart of a manual activation mode of a method fordetecting an exit of a patient from the bed, in accordance with oneembodiment.

FIG. 3 is a flowchart of an automatic activation mode of a method fordetecting an exit of a patient from the bed, in accordance with oneembodiment.

FIG. 4 is a diagram of a touchscreen for the hospital bed systemillustrated in FIG. 1, displaying a window including text indicatingthat the presence of a patient has been detected on the bed.

FIG. 5 is another diagram of the touchscreen for the hospital bed systemillustrated in FIG. 1, displaying a main interface image duringmonitoring of the exit of the patient from the bed.

FIG. 6 is yet another diagram of the touchscreen for the hospital bedsystem illustrated in FIG. 1, displaying a pause confirmation windowwhich allows a user to input a pause command.

FIG. 7 is still another diagram of the touchscreen for the hospital bedsystem illustrated in FIG. 1, displaying again the main interface imagewhile the exit detection system is in a pause mode and including adecreasing timer indicating an amount of time remaining beforeexpiration of a predetermined pause time.

FIG. 8 is another diagram of the touchscreen for the hospital bed systemillustrated in FIG. 1, displaying a pause option window which allow theuser to selectively exit the pause mode and to increase the amount oftime remaining before expiration of the predetermined pause time.

FIG. 9 is a diagram of the touchscreen for the hospital bed systemillustrated in FIG. 1, displaying a calibration menu image including astart button and a tare weight condition recall button.

FIG. 10 is another diagram of the touchscreen for the hospital bedsystem illustrated in FIG. 1, displaying a tare weight condition recallmenu image including text indicative of a plurality of previous measuredtare weight conditions.

FIG. 11 is a flowchart of a method for recalibrating a tare weightcondition of a hospital bed, in accordance with one embodiment.

FIG. 12 is a block diagram showing a hospital bed system for a hospitalbed, in accordance with an alternative embodiment, in which the hospitalbed includes an elevation mechanism and a bed height limiting system.

FIG. 13 is a flowchart of a method for limiting the height of thehospital bed illustrated in FIG. 12.

FIG. 14 is a diagram of a touchscreen for the hospital bed systemillustrated in FIG. 12, displaying a preference image which includes aheight configuration button.

FIG. 15 is another diagram of the touchscreen for the hospital bedsystem illustrated in FIG. 12, displaying a minimum height adjustmentimage which allows a user to select one of a plurality of predeterminedminimum height values.

DETAILED DESCRIPTION

Referring first to FIG. 1, there is provided a hospital bed system 100for a hospital bed 102, in accordance with one embodiment. It will beunderstood that in the following description, the term “hospital bed” isused to refer to any type of bed which is adapted to receive a patient,including hospital beds and long term care beds, and is not limited foruse in a hospital.

In the illustrated embodiment, the bed 102 includes a frame 104 and apatient receiving surface 106 supported by the frame 104 for receiving apatient. Specifically, the patient receiving surface is generallyrectangular and includes a deck of the hospital bed 102. The patientreceiving surface 106 could further includes a mattress, not shown,disposed on the deck and onto which the patient may lie.

In the illustrated embodiment, the hospital bed system 100 furtherincludes an exit detection system 110 for detecting an exit of a patientfrom the bed 102. More specifically, the exit detection system 110includes a patient location sensor 112 operatively coupled to the bed102 for determining a location of a patient on the bed 102, a processingunit 114 operatively coupled to the patient sensor and a bed exit alarm116 operatively connected to the processing unit 114 for providing anindication to a user that an exit of the patient from the bed 102 hasbeen detected. The processing unit 114 is configured for receiving fromthe patient location sensor 112 an indication that the patient hasexited the bed 102. Specifically, the processing unit 114 may beconfigured for receiving from the patient location sensor 112 anindication that the patient has exited the patient receiving surface106. Even more specifically, the processing unit 114 may be configuredfor receiving from the patient location sensor 106 an indication thatthe patient has exited a predetermined patient area 108 on the patientreceiving surface 106. In this case, a detection of movement of thecenter of mass of the patient from the predetermined patient area 108would be indicative of the patient exiting the bed 102, and the bed exitalarm 116 could be activated in accordance to one or more desiredconditions such as a detected movement speed of the patient's center ofmass on the patient receiving surface 106 and/or a period for which thepatient is detected as having left the patient support surface 106.

An example of a system for determining a location of a patient on a bed,or patient location determination system, is described in U.S. Pat. No.9,754,476, a copy of which is incorporated herein by reference. Thissystem can be used for monitoring whether the patient is in thepredetermined patient area 108 or if the patient exits the predeterminedpatient area 108, as a skilled person will appreciate.

In one embodiment, the predetermined patient area 108 could berectangular and generally smaller than the patient receiving area 106,such that the predetermined patient area 108 is generally centered onthe patient receiving area 106 and is surrounded by a border area of thepatient receiving surface 106. Alternatively, the predetermined patientarea 108 could correspond generally to the entire patient receivingsurface 106.

In one embodiment, the processing unit 114 is further configured forreceiving an indication that a patient is present on the bed 102 andupon receiving the indication that the patient is present on the bed102, to set the system in a monitoring configuration in which thepresence of the patient on the bed 102 is monitored. In other words,when a presence of a patient is initially detected on the bed 102, thesystem is “armed” and ready to detect an exit of the patient from thebed 102.

In one embodiment, the bed 102 further includes a weight sensingassembly 120 operatively connected to the patient receiving surface 104to measure a weight of a patient received on the patient receivingsurface 106. In the present embodiment, the weight sensing assembly 120could further be used to detect the presence of a user on the bed 102.Specifically, the weight sensing assembly 120 could include one or moreweight sensors disposed between the patient receiving surface 106 andthe frame 104. In another embodiment, the weight sensing assembly 120could include one or more sensors disposed between a base of the bed 102located near the ground surface and an elevation mechanism located abovethe base, as described in U.S. Pat. No. 9,754,476, a copy of which isincorporated herein by reference. Alternatively, the weight sensingassembly 120 could include any other type of weight sensors orcombination of weight sensors which may be located at differentlocations on the bed 102.

In another embodiment, instead of the weight sensing assembly 120, theprocessing unit 114 could be configured to detect the presence of thepatient on the bed 102 using the patient location sensor 112 instead ofthe weight sensing assembly 120, or even using a combination of thepatient location sensor 112 and of the weight sensing assembly 120.

In one embodiment, the exit detection system 110 further includes a userinterface 122 operatively connected to the processing unit 114 to allowa user to input and/or modify parameters of the exit detection system110. The bed 102 may further include a display 124 operatively connectedto the processing unit 114 for displaying data related to the bed 102 tothe user. In one embodiment, both the user interface 122 and the display124 include a common touchscreen, which can both display data to a userand allow the user to input commands to the processing unit 114.

In one embodiment, the bed 102 may further include a memory 126operatively connected to the processing unit 114 for storing one or moreparameters inputted by the user via the user interface 122.

In one embodiment, the bed exit alarm 116 includes a visual indicatoroperatively connected to the processing unit 114. Specifically, thevisual indicator may include one or more indicator lights, such asLED-based lights or incandescent lights, which may be located on anexterior surface of the bed 102 such as a side surface of the bed 102 soas to be visible to a user standing away from the bed. The indicatorlights may provide to the user a visual indication of a specificcondition or event, such as an exit of the patient from the bed 102. Forexample, the processing unit 114 may be configured to cause theindicator lights to flash intermittently when an exit of the patientfrom the bed 102 is detected.

Moreover, the indicator lights may each be configured to be selectivelylit in one of a plurality of colors depending on the visual indicationwhich is to be provided to the user. For example, the processing unit114 may be configured to cause the indicator lights to be lit up in anorange color and to flash intermittently to provide an indication thatan exit of the patient from the bed 102 is detected. The processing unit114 may further be configured to cause the indicator lights to be lit upin a green color and to remain continuously lit when the system 110 isarmed, but that no exit of the patient from the bed 102 is detected. Itwill be understood that other colors and other combinations are alsopossible.

The bed exit alarm 116 may further include an audible alarm whichproduces a sound indicative of the patient exiting the bed 102. The bedexit alarm 116 could also be remote from the bed 102, at a controlstation operatively connected to multiple hospital beds for example.

Now turning to FIGS. 2 and 3, there is shown a method for detecting anexit of a patient from the bed 102, in accordance with one embodiment.

In this embodiment, the system 110 is first set into one of a manualactivation mode 200, illustrated in FIG. 2, and an automatic activationmode 300, illustrated in FIG. 3.

Referring first to FIG. 2, in the manual activation mode 200, the system110 is first simply armed by a user, in accordance with 202.Specifically, the user may manually input into the user interface 122 acommand to start monitoring an exit of the patient from the bed 102. Theprocessing unit 114, operatively coupled to the user interface 122,receives the command to start monitoring the exit of the patient.According to 204, the system 110 first confirms that the patient is inthe predetermined patient area 108 on the bed 102.

In one embodiment, before the user manually inputting the command tostart monitoring the exit of the patient from the bed 102, the patientis placed on the bed 102 and the user visually confirms that the patientis properly received on the patient receiving surface 106. In oneembodiment, the user must specifically confirm that the patient is inthe predetermined patient area 108 of the patient receiving surface 106,such that the exit of the patient from the predetermined patient area108 may then be monitored.

According to 206, the bed exit detection system 110 is then armed suchthat the exit of the patient from the predetermined patient area 108 ismonitored. While monitoring the exit of the patient from the bed 102,the processing unit 114 may further cause the indicator lights toprovide to a user an indication that the exit of the patient from thebed 102 is being monitored. For example, the indicator lights may belighted continuously in a green color. Alternatively, the indicatorlights may flash in a predetermined pattern and/or be lighted in adifferent color. In yet another embodiment, the system 110 may onlyprovide an indication to the user that the exit of the patient from thebed 102 is being monitored via the display 124, rather than via theindicator lights.

According to 208, when the patient location sensor 112 detects that thepatient location moves from the predetermined patient area or zone 108to outside the predetermined patient area 108, the processing unit 114receives an indication that the patient is exiting the bed 102 andactivates the bed exit alarm 116 in accordance with 210. Specifically,the processing unit 114 lights the indicator lights in an orange colorand causes the indicator lights to flash intermittently, therebyproviding to a user standing near the bed an indication that the patientis exiting the bed 102.

According to 212, the user may then manually deactivate the bed exitalarm 116. For example, the bed exit alarm 116 may be deactivated by theuser via the touchscreen. Alternatively, the bed exit alarm 116 couldalso be deactivated automatically after a predetermined bed alarm time.

Furthermore, according to 214, even if the bed exit alarm 116 has notbeen activated, the user may still interrupt the monitoring of the exitof the patient from the bed 102 manually, by entering a correspondinginput command into the user interface 122, for example.

Referring now to FIG. 3, instead of being set in the manual activationmode 200, the system 110 may be set in the automatic activation mode300.

If a command to set the system in the automatic activation mode 300 isreceived, the presence of a patient on the bed 102 is first monitored inaccordance with 302. Specifically, the presence of a patient on thepatient receiving surface 106 is monitored. In one embodiment, thepresence of a patient on the patient receiving surface 106 is monitoredusing the weight sensing assembly 120. For example, the weight sensingassembly 120 may provide to the processing unit 114 an indication that apatient is received on the bed 102 when a weight above a predeterminedweight threshold has been detected on the bed 102. In one embodiment,the predetermined weight threshold is 70 lb or about 32 kg. It will beappreciated that this weight threshold may contribute to confirming thata patient is actually received on the bed, rather than merely one ormore objects being deposited on the bed or someone leaning on the bed.Alternatively, the predetermined weight threshold could be more or lessthan 70 lb or about 32 kg.

In one embodiment, before the indication that the patient is received onthe bed 102 is received by the processing unit 114, the patient locationsensor 112 may be in a non-active mode in which the location of thepatient on the patient receiving surface 106 is not monitored.Specifically, the patient location sensor 112 can simply be turned off,such that it does not require any power and therefore does not consumeany energy. Alternatively, the patient location sensor 112 could be in alow-power mode which requires relatively little power and thereforeconsumes relatively little energy.

In one embodiment, once the indication that the patient is on the bed102 is provided by the weight sensing assembly 120 and received by theprocessing unit 114, the indication is provided by the processing unit114 to the display 124 and is displayed on the display 124.

According to 304, the processing unit is configured to receive anindication that the patient is positioned in the predetermined patientarea 108 and that the patient is not moving, or stable.

Referring now to FIG. 4, the indication may include a window 400including text indicating that the presence of the patient has beendetected on the bed 102 and a confirmation button 402 which can beactivated by the user to provide the indication that the patient ispositioned in the predetermined patient area 108 and that the patient isstable.

In an embodiment in which the display 124 and the user interface 122 isa touchscreen, the user may activate the confirmation button 402 byinteracting with the touchscreen.

Alternatively, instead of the user providing the indication that thepatient is in the predetermined patient area 108 and stable, theindication may be provided automatically by the patient location sensor112. For example, the indication may be provided if the presence of thepatient in the predetermined patient area 108 is detected and if nomovement of the patient on the patient receiving surface 106 is detectedfor a predetermined time. On the other hand, if movement of the patientis detected, or if the presence of the patient on the bed 102 isdetected but the presence of the patient in the predetermined patientarea 108 is not detected, indicating that the patient is on the bed 102but not properly placed in the predetermined patient area 108, then thepatient location sensor 112 will not provide the indication that thepatient is in the predetermined patient area 108 and stable.

In one embodiment, the window 400 may further include a decreasing timer404 indicating an amount of time remaining before expiration of a firstpredetermined time. If the indication that the patient is in thepredetermined patient area 108 and stable is not provided beforeexpiration of the first predetermined time, the bed exit alarm 116 isactivated by the processing unit 114. In one embodiment, the firstpredetermined time is 60 seconds. Alternatively, the first predeterminedtime may be longer or shorter.

In one embodiment, the bed exit alarm 116 includes the processing unit114 lighting the indicator lights in an orange color and causes theindicator lights to flash intermittently, as described above.Alternatively, the bed exit alarm 116 could include other types ofalarms.

Referring back to FIG. 3, once the indication that the patient is in thepredetermined patient area 108 and stable is received by the processingunit 114, the exit of the patient from the predetermined patient area108 may then be monitored using the patient location sensor 112 inaccordance with 306. While monitoring the exit of the patient from thebed 102, the processing unit 114 may cause the indicator lights toprovide to a user an indication that the exit of the patient from thebed 102 is being monitored, for example by lighting the indicator lightscontinuously in a green color as described above.

According to 308, when the patient location sensor 112 detects that thepatient location moves from the predetermined patient area or zone 108to outside the predetermined patient area 108, the processing unit 114receives an indication that the patient is exiting the bed 102 andactivates the bed exit alarm 116 in accordance with 310 and as describedabove. Specifically, the processing unit 114 lights the indicator lightsin an orange color and causes the indicator lights to flashintermittently, thereby providing to a user standing near the bed anindication that the patient is exiting the bed 102.

According to 312, during the monitoring of the exit of the patient fromthe bed 102, the user may input a pause command which sets the system ina pause mode 314 in which the monitoring of the exit of the patient fromthe bed 102 is temporarily interrupted. Specifically, even if thepatient moves or is moved from the predetermined patient area 108 tooutside the predetermined patient area 108 while the system is set inthe pause mode 314, the bed exit alarm 116 will not be activated.

It will be appreciated that it may be desirable to temporarily interruptthe monitoring of bed exit to access the patient in order to providecare to the patient, which may require temporarily moving the patientoutside of the predetermined patient area 108. Care to the patient couldinclude washing the patient, performing examinations on the patient,changing the sheets, or any other type of care.

In one embodiment, when the pause command is received, a pause indicatoris also activated, thereby indicating to the user that the bed exitsystem is in the pause mode 314. In one embodiment, the pause indicatorincludes the indicator light being lighted continuously in an orangecolor. Alternatively, the pause indicator may include another visualindicator or any other type of indicator.

FIG. 5 shows a main interface image 500 which may be displayed on thedisplay 124 during monitoring of the exit of the patient from the bed102. The main interface image 500 could include an indication that thesystem 110 is armed and that the exit of the patient from the bed 102 istherefore monitored.

In the illustrated embodiment, the main interface image 500 includes apause button 502 which can be activated by the user to display a pauseconfirmation window 600, as shown in FIG. 6. In the illustratedembodiment, the pause confirmation window 600 includes a confirmationbutton 602 which can be activated by the user to provide a pause commandto the processing unit 114. Still in the illustrated embodiment, thepause confirmation window 600 further includes a cancellation button 604which closes the pause confirmation window 600 and returns the display124 to the main interface image 500 shown in FIG. 5.

Once the confirmation button has been activated by the user, the maininterface image 500 may be displayed on the display 124 and may includetext indicative that the system 110 is currently set in the pause mode314. In the illustrated embodiment, the main interface image 500 furtherincludes a decreasing timer 700 indicating an amount of time remainingbefore expiration of a predetermined pause time. Specifically, thedecreasing timer 700 may be displayed on the pause button 502, as shownin FIG. 7.

When the system 110 is in the pause mode 314, the pause button 502 mayfurther be activated by the user to display a pause option window 800,as shown in FIG. 8. In the illustrated embodiment, the pause optionwindow 800 includes a pause cancellation button 802, a timer increasebutton 804 and a window closing button 806. The pause cancellationbutton 802 can be activated by the user to exit the pause mode 314 andthe method can be repeated from step 302, starting again with monitoringthe presence of the patient on the bed 102. The timer increase button804 can be activated by the user to increase the amount of timeremaining before expiration of the predetermined pause time by apredetermined time increment. In one embodiment, the predetermined pausetime is initially 2.5 minutes and the predetermined time increment is 5minutes. Alternatively, the initial predetermined pause time and thepredetermined time increment may be different. Finally, the windowclosing button 806 can be activated by the user to close the pauseoption window 800 and return the display to the main interface image 700shown in FIG. 7.

After expiration of the predetermined pause time, the system 110 exitsthe pause mode 314. Specifically, the presence of the patient on the bed102 is once again monitored, and the system may repeat step 302 and thefollowing steps.

In one embodiment, in addition to the system 110 being set in the pausemode 314 upon receipt of a pause command from the user, the system 110may further be set to pause mode 314 when the processing unit 114receive an indication that, following a manual deactivation of the bedexit alarm 116 by the user, a patient is still received on the bed inaccordance with 316 of FIG. 3. This could indicate that the user wantsto temporarily suspend the monitoring of bed exit while attending to thepatient on the bed 102.

It will be appreciated that the use of the automatic activation mode 300advantageously allows the patient location sensor 112 to only beactivated and used if the presence of a patient on the bed 102 is firstdetected, which reduces the overall energy consumption of the system110.

Furthermore, by providing a visual indication to the user that a patientis received on the bed 102 by displaying window 400, the system 110further provides to the user an indication that the patient must beplaced properly in the predetermined patient area 108, therebycontributing to ensure that the user confirms that the user is in thepredetermined patient area 108 before the start of the monitoring of thepatient exiting the bed 102. This may help to prevent situation in whichthe patient is outside the predetermined patient area 108 when themonitoring of the patient exiting the bed 102 is started, in which casethe bed exit alarm 116 would immediately be activated.

The use of the pause mode 314 may also contribute to preventing the userfrom forgetting to re-arm the bed exit detection system 110 once thesystem 110 is interrupted in order to provide care to the patient.

In one embodiment, the processing unit 114 may further be configured toallow a tare weight condition to be measured to obtain propermeasurements from the weight sensing assembly 120 and from the patientlocation sensor 112. Specifically, measuring the tare weight conditionincludes installing required medical equipment on the bed 102, theprocessing unit 114 receiving a measure of weight and of patientlocation from the weight sensing assembly 120 and from the patientlocation sensor 112 before the patient is received on the bed 102 andstoring the initial weight measurement the initial location measurementin the memory 126. This initial weight measurement will thereforerepresent a value of zero, with further weight measured by the weightsensing assembly 120 representing a difference between the measuredweight and the initial weight measurement. Similarly, the initialpatient location measurement will represent a value of zero, or alocation centered on the patient receiving surface, with furtherlocation measurement by the patient location system being calculatedaccording to this initial position measurement.

FIG. 9 shows a calibration menu image 900 displayed on the display 124.In this embodiment, the calibration menu image 900 includes a startbutton 902 which can be activated by the user to instruct the processingunit 114 to receive the initial weight and location measurements.

In the illustrated embodiment, the calibration menu image 900 furtherincludes a tare weight condition recall button 904 which can beactivated by the user to cause the display to display a tare weightcondition recall menu image 1000 as shown in FIG. 10. The tare weightcondition recall menu image 1000 includes text indicative of a pluralityof previous measured tare weight conditions 1002, a cursor 1004 forselecting one of the previous measured tare weight conditions 1002 and apair of scroll buttons 1006 to move the cursor 1004 between the previousmeasured tare weight conditions 1002. In the illustrated embodiment, theplurality of previous measured tare weight conditions 1002 includes thelast four tare weight conditions measured. Alternatively, the pluralityof previous measured tare weight conditions 1002 could include more orless previously measured tare weight conditions. Still in theillustrated embodiment, the tare weight condition recall menu image 1000includes an apply button 1008 which can be activated by the user toapply the selected tare weight condition such that the current tareweight condition are replaced by the selected tare weight condition.

Now referring to FIG. 11, there is provided a method 1100 forrecalibrating a tare weight condition of a hospital bed, in accordancewith one embodiment.

According to 1102, the user first inputs a command for applying thecurrent measured tare weight condition, also referred to as “zero”, tothe processing unit 114 via the user interface 122.

According to 1104, the processing unit receives from the weight sensingassembly 120 an indication of the bed weight and of the current measuredweight. In this embodiment, medical equipment is received on the bed 102and creates a difference between the bed weight and the current measuredweight. Therefore, the processing unit 114 calculates the differencebetween the bed weight and the current measured weight representing theequipment weight. The equipment weight may further be stored in thememory 126, where it is associated to a tare weight condition whichincludes a current weight measurement and a current locationmeasurement.

According to 1106, when the user inputs a command to recall the previoustare weight conditions, the processing unit 114 receives the command.The processing unit 114 therefore communicates with the memory 126 toretrieve the predetermined number of tare weight conditions stored inthe memory 126.

According to 1108, the last four tare weight conditions are thendisplayed on the display 124, as described above. Specifically, eachtare weight condition is associated with an equipment weight, which wascalculated as explained above.

According to 1110, the user selects the tare weight condition based onthe appropriate equipment weight corresponding to the equipment weightcurrently on the bed 102 and the selected tare weight condition isapplied. Specifically, according to 1112, the patient weight can becalculated as the difference between the current measured weight and asum of the bed weight and the selected equipment weight, and thecalculated weight may be displayed on the display 124.

It will be appreciated that this method advantageously acts as an “undo”function in case the tare weight condition is mistakenly measured andset while the patient is received on the bed. With the present method,the tare weight conditions can be set to an accurate value based on aprevious measurement without having to remove the patient from the bed102 to perform a tare weight condition measurement again.

In one embodiment, the processing unit 114 is further adapted to displayan image including a plurality of command buttons which can be activatedby the user and which may each be provided with a pictogram which isrelated to the function of the command button. This may help facilitatethe use of the user interface. Pictograms may also be used to showdifferent data or indication related to the bed or to the safety of thepatient received on the bed.

In one embodiment, the bed system 100 further includes a communicationunit 150 operatively connected to the processing unit 114, as shown inFIG. 1, for allowing communication of the processing unit 114 with aremote device 152. In one embodiment, the remote device 152 is apersonal computer. Alternatively, the remote device 152 could be asmartphone, a tablet of any other types of devices.

In one embodiment, the communication unit 150 includes a WiFi antennaadapted for wirelessly communicating with the remote device.Alternatively, the communication unit 150 could include a USB port forconnecting the remote device 152 to the processing unit using a USBcable and protocol.

In one embodiment, the remote device 152 includes a computer programwhich enables the exchange of data between the remote device 152 and theprocessing unit 114 and the memory 126. In one embodiment, the computerprogram is accessible through a web browser.

In one embodiment, the computer program is configured to receive one ormore images or pictograms provided by the user and to format the one ormore images or pictograms so as to make them compatible with theprocessing unit 114 of the bed 102. The computer program may further beconfigured to allow access to the processing unit 114 fortroubleshooting purposes.

It will be appreciated that the computer program may be used to transferdata to and from processing units of multiple beds simultaneously.

Now turning to FIG. 12, there is shown a hospital bed system 1200 for ahospital bed 1202, in accordance with another embodiment.

In this embodiment, the bed 1202 includes a frame 1204 and a patientreceiving surface 1206 supported by the frame 1204 for receiving apatient. Specifically, the patient receiving surface is generallyrectangular and includes a deck of the hospital bed 1202. The patientreceiving surface 1206 could further includes a mattress, not shown,disposed on the deck and onto which the patient may lie.

Still in the embodiment illustrated in FIG. 1200, the bed 1202 furtherincludes an elevation mechanism 1210 secured to the frame 1204 andlocated under the frame 1204 for moving the patient receiving surface1206 vertically relative to a ground surface on which the bed 1202 isplaced.

In one embodiment, the elevation mechanism 1210 may include a frontelevation assembly located near a front end of the bed 1202 and a rearelevation assembly located near a rear end of the bed 1202. Thisconfiguration allows the bed 1202 to be angled relative to the groundsurface by actuating one of the front and rear lift assemblies such thatone of the front and rear ends of the bed 1202 is located higher thanthe other one of the front and rear ends of the bed 1202. To raise orlower the bed, both the front elevation assembly and the rear elevationassembly are actuated simultaneously such that the front and rear endsof the bed are raised or lowered simultaneously. Each one of the frontand rear elevation assembly may include one or more actuators such aslinear actuators or any other type of actuators which is skilled personwould consider to be appropriate.

An example of an elevation mechanism, or elevation system, is describedin US Patent Publication No. 2016/0058639, a copy of which isincorporated herein by reference. Alternatively, the elevation mechanismcould be configured differently.

In the illustrated embodiment, the bed 1202 further includes a pluralityof casters 1208, and the front and rear elevation assemblies extendbetween the casters 1208 and the patient receiving surface.Alternatively, the bed 1202 may not include casters.

Still in the illustrated embodiment, the hospital bed system 1200further includes a bed height limiting system 1250 for limiting theheight of the patient support surface 1206 to a minimum height. The bedheight limiting system 1250 includes a height sensor 1252 operativelyconnected to the bed 1202, a processing unit 1254 operatively connectedto the bed 1202 and a user interface 1256 operatively connected to theprocessing unit 1254. The processing unit 1254 is configured forreceiving a minimum height value provided by the user via the userinterface 1256. In one embodiment, the bed height limiting system 1250further includes a memory 1258 operatively connected to the processingunit 1254 for storing the minimum height value.

In one embodiment, the height sensor 1252 is operatively connected tothe actuators of the elevation mechanism 1210. Specifically, theprocessing unit 1254 may be configured to calculate a height between abottom end and a top end of the front and rear elevation assemblies byreceiving a measurement of extension from the actuators, correspondingto a length by which the actuators are extended. Alternatively, theheight sensor may instead include another type of sensor such as anoptical sensor or any other type of sensor which a skilled person wouldconsider appropriate.

In one embodiment, the processing unit is configured to calculate theheight of the patient support surface 1206 relative to the groundsurface by adding the calculated height of the elevation mechanism 1210with a height of the casters 1208. In one embodiment, the height of thecasters 1208 is pre-entered in the memory 1258 and is provided to theprocessing unit 1254 from the memory 1258. Alternatively, the user mayenter the height of the casters 1208 manually in the memory 1258 throughthe user interface 1256.

In the illustrated embodiment, the processing unit 1254 is furtheroperatively connected to the elevation mechanism 1210 and is configuredto detect a downward motion of the elevation mechanism.

In one embodiment, the bed 1202 may further include a display 1260operatively connected to the processing unit 1254 for displaying datarelated to the bed 1202 to the user. In one embodiment, both the userinterface 1256 and the display 1260 include a touchscreen, which canboth display data to a user and allow the user to input commands to theprocessing unit 1254 and to provide parameters into the memory 1258.

Now turning to FIG. 13, there is shown a method 1300 for limiting theheight of the hospital bed 1202, in accordance with one embodiment. Asexplained above, the height of the hospital bed 1202 corresponds to theheight of the patient receiving surface 1206 relative to the groundsurface.

According to 1302, the minimum height value is first provided by theuser. Specifically, the minimum height value may be provided into thememory 1258 via the user interface 1256.

FIG. 14 shows a preference image 1400 displayed on the display. Thepreference image 1400 includes a height configuration button 1402 whichmay be activated by the user to provide the minimum height value or tomodify the minimum height value currently entered or selected in thememory 1258. In one embodiment, the activation of the heightconfiguration button 1402 is password-protected such that acorresponding password must be inputted in order to activate the heightconfiguration button 1402.

In the illustrated embodiment, activating the height configurationbutton 1402 causes the display 1260 to display a minimum heightadjustment image 1500 as shown in FIG. 15. Still in the illustratedembodiment, the minimum height adjustment image 1500 includes a pair ofscrolling buttons 1502 which can be activated by the user to cyclethrough a plurality of predetermined minimum height values 1504 providedfrom the memory 1258, in order to select one of the predeterminedminimum height values. In one embodiment, the predetermined minimumheight values range from 10 inches to 16 inches when the casters 1208 ofthe bed 1202 include dual casters, and from 11½ inches to 17½ incheswhen the casters 1208 include single casters. Alternatively, the usercould instead manually enter a desired minimum height value into thememory 1258 via the user interface 1256.

Referring back to FIG. 13, according to 1304, the caster height or wheelsize is further provided, as explained above.

According to 1306, an indication of the current height of the elevationmechanism 1210 is further provided by the height sensor 1252 to theprocessing unit 1254.

According to 1308, the current height of the bed 1202 is then computedor calculated by the processing unit 1254 based on the caster height andthe indication from the height sensor 1252.

According to 1310, vertical movement of the elevation mechanism 1210 isthen monitored. Specifically, if the elevation mechanism 1210 is loweredsuch that the patient support surface 1206 moves towards the groundsurface, an indication that the elevation mechanism 1210 is movingdownwardly is received by the processing unit 1254 from the elevationmechanism 1210.

According to 1312, upon receiving an indication that the patientreceiving surface 1206 is moving downwardly, the processing unit 1254compares the calculated current height with the selected minimum heightvalue. If the current height is equal to the selected minimum heightvalue, the processing unit 1254 stops the elevation mechanism 1210 andprevents the elevation mechanism 1210 from further moving downwardly, inaccordance with 1314.

According to 1316, the processing unit 1254 further provides anindication to the user that the selected minimum height value has beenreached. For example, the indication could include a visual indicator,such as text, provided on the display 1260 to indicate to the user thatthe selected minimum height value has been reached.

It will be appreciated that this height limiting system 1250 may helppreventing damage to medical equipment, cables or other objects whichmay be stored under the patient support surface. The height limitingsystem 1250 may also advantageously allow the minimum height value to bechanged and adjusted according to the size of the items stored under thebed, or to the configuration of the room and of the ground surface belowthe bed.

I/We claim:
 1. A method for limiting a height of a hospital bed, thehospital bed including an elevation mechanism for moving a patientreceiving surface of the bed vertically relative to a ground surface,the method including: providing an indication of a minimum height valueto a processing unit operatively connected to the elevation mechanism;providing a current height of the bed to the processing unit; detectinga downward vertical movement of the elevation assembly; the processingunit comparing the current height of the bed with a predeterminedminimum height value; if the current height of the bed is equal to thepredetermined minimum height value, stopping the downward movement ofthe elevation assembly.
 2. The method as claimed in claim 1, whereinproviding a current height of the bed comprises: providing an indicationof a caster height of bed casters to the processing unit; the processingunit receiving from a height sensor operatively connected to theelevation mechanism a current height of the elevation mechanism; theprocessing unit calculating the current height of the bed based on theindication of the caster height and the current height of the elevationmechanism.
 3. The method as claimed in claim 1, wherein stopping thedownward movement of the elevation assembly comprises: the processingunit providing a command to the elevation mechanism to stop downwardmovement of the elevation assembly.
 4. The method as claimed in claim 1,further comprising: if the current height of the bed is equal to thepredetermined minimum height value, providing an indication to a userthat the patient elevation surface is at the predetermined minimumheight value.